<?php

/*
 * Copyright 2008 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#namespace tehframework\filtering;

class AlphabeticFilter implements Filter
{
	public function filterValue($rawValue)
	{
		if (!is_string($rawValue))
		{
			return '';
		}
		
		if (ctype_alpha($rawValue))
		{
			return $rawValue;
		}
		
		return preg_replace('@[^A-Za-z]@s', '', $rawValue);
	}
}